Liquid crystal displays operating on relatively low electric power have found a wide range of applications as image displays for fixed types of devices, as well as for mobiles. Some of these liquid crystal displays include liquid crystal cells of vertically aligned mode and normally black mode as a display element for improved viewing angle characteristics and contrast ratio.
Examples are disclosed in Japanese published patent application 11-109391/ 1999 (Tokukaihei 11-109391; published on Apr. 23, 1999) and Japanese published patent application 11-258605/1999 (Tokukaihei 11-258605; published on Sep. 24, 1999) which will be detailed later. Each liquid crystal display is of vertically aligned mode and contains a vertically aligned film and a liquid crystal with negative dielectric anisotropy. In the absence of applied voltage, liquid crystal molecules align vertically. Linearly polarized light incident from a polarizer on a liquid crystal layer under these conditions leaves the liquid crystal layer while retaining its polarization, because the liquid crystal layer has little birefringence (optical anisotropy). The light is then absorbed by a polarizer positioned on the opposite side of the liquid crystal layer. The liquid crystal display thus achieves a black display.
In contrast, when a voltage is applied, liquid crystal molecules in the liquid crystal layer tilt in accordance with the applied voltage. Linearly polarized light incident from a polarizer on a liquid crystal layer under these conditions develops phase difference in the liquid crystal layer. The light thus changes its polarization. Therefore, the light, upon leaving the liquid crystal cell, typically becomes elliptically polarized.
The elliptically polarized light then hits another polarizer located on the light-emitting side of the liquid crystal cell. The elliptically polarized light only partially passes through the polarizer, which is different from the event in the absence of applied voltage; the amount of light that is transmitted depends on the phase difference provided by the liquid crystal layer. Thus, the amount of light leaving the liquid crystal display can be altered by adjusting the alignment direction of the liquid crystal molecules through the control of the applied voltage to the liquid crystal layer. The altering of the amount of light enables a grayscale display.
However, liquid crystal displays which include as a display element a liquid crystal cell of vertically aligned mode and normally black mode can suffer motion blurriness and other display quality degradation when displaying moving images. Further display quality improvements are needed.